In British Columbia, due to the decline of lodgepole pine, mills should expect higher volumes of sub-alpine fir in their species mix. The impact on drying is significant. For example, drying times for green SPF (spruce, pine, sub-alpine fir) vary from 24 to 36 hours whereas drying times for sub-alpine fir can easily exceed 70 hours. In addition to longer drying times, the drying of species such as sub-alpine fir using current procedures often results in wet lumber and value loss can be higher than $100 per Mfbm. The potential annual impact for a typical BC mill is estimated to be in the range $1,000,000 to $1,500,000.
Along the years, sawmills have invested millions of dollars in drying technology (conventional drying and green sorting systems) which, for the most part are efficient and relatively low cost. Thus, under the circumstances outlined above, sawmills urgently need to find ways to minimize the problems associated with the drying of sub-alpine fir that is, new procedures or combination of methods, to ensure maximum grade recovery at the end of drying and reduce drying times (increase productivity and lower processing costs). In addition, the pressure exerted by typical longer drying times for sub-alpine fir will impact the drying of spruce and pine. Thus, strategies to speed the drying for those two species are needed to maintain annual production targets.
The main objective of this project is to evaluate several strategies using existing technology so that sawmills can readily implement them throughout their drying operations dealing with larger volumes of sub-alpine fir and for mills with kiln capacity constraints which could compromise their production targets.
This project evaluated a number of opportunities to coastal producers related to kiln drying issues such as drying practices related to high-value products, drying with superheated steam vacuum and internal core temperature monitoring for large timbers during the heat-up phase. In summary, this project included several laboratory studies to evaluate the using superheated steam/vacuum (SS/V) for drying 7/8”x 6, green western red cedar lumber, and 8x8 and 5x(5,6,7,8,9,10,12) Douglas-fir timbers. SS/V drying yielded faster drying schedules when compared to the results obtained in industrial conventional kilns. The results obtained from the SS/V drying of WRC indicated the potential benefits of technology for drying specialty products especially when compared to drying times obtained with conventional drying (longer than 7 days). However, the results obtained also emphasize the importance of green sorting that is, sorting prior to drying to optimize drying times and reduce the variation of final moisture content.
For large cross section Douglas-firs the drying times were between 3 and 14 days depending on the severity of the drying schedule and initial moisture content distribution. The influence of moisture content and cross section during the early and late stages of the heating process were evaluated on 5x5, 6x6 and 8x8 Douglas fir timbers. Thermodynamic equilibrium was reached after 20 hours regardless of moisture content or cross section size. The knowledge is intended to be used to design conventional drying schedules for large cross section timbers.
According to the last forecasts released by BC Hydro, in 20 years the demand for electricity in B.C. will increase about 40%. A typical sawmill in Canada has between 4 and 8 kilns which operate on a constant basis throughout the year. Each kiln dries on average about 16 to 20 kiln charges per month and every kiln charge is on average 250 Mfbm of lumber (based on 2-inch thickness). A typical crossshaft kiln is equipped with fifteen 25 hp motors (approximately 18 kW) so the total installed power per
kiln is about 270 kW. Kilns operate an average of 660 hours per month. Thus, mills with drying operations such as in the example above will consume a significant amount of electricity to dry their
required production.
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Effective preservative treatments for Canadian glulam products are needed to maintain markets for mass timber on building facades, access markets with significant termite hazards, and expand markets for wood bridges. For all three applications, borate-treatment of lamina before gluing would be preferred as it would lead to maximum preservative penetration. However, the need to plane after treatment and prior to gluing removes the best-treated part of the wood, and creates a disposal issue for treated planer shavings. The present research evaluates the block shear resistance of glulam prepared from untreated and borate-treated lamina with a polyurethane adhesive. Borate treatment was associated with a small but statistically significant loss in median shear strength when evaluated dry; however, there was no difference between the performance of untreated and borate-treated samples when exposed to the vacuum-pressure soak/dry or the boil-dry-freeze/dry procedures. Further work is needed to modify the composition or application of the resin to improve shear strength for glulam applications and ensure consistent performance. However, overall, these data indicate that samples prepared from borate-treated lamina perform similarly in terms of block shear resistance to those prepared from untreated lamina.
This study develops and tests a simple model for the effect of knots on MOR: assuming that a knot is hole in the cross-section of a board a strength ratio is calculated and the MOR is the product of the strength ratio and the strength (MOR) of clear wood. This knot model is based on the stresses being in the elastic range and ignores the effect of grain angle and the orthotropic properties of wood and so should not accurately predict either loads for initial failure or the loads at final failure, on which MOR is based. However, the predicted values of MOR for SPF and Douglas fir compare well to measured values. This lead to the conclusion that while the model is physically wrong, the results imply that the strength ratio of the knot model are related to the strength ratio at final failure, which usually occurs at the end of a crack that starts at the knot but propagates some distance along the board. A model for the strength of the remaining section at the end of the crack was developed and tested on six boards. Not only were the strength ratios for the remaining section model similar to those of the knot model, but the remaining section model predicted MOR values closer to the measured values than the knot model did. The task of future work is to predict the location of the initial crack, the path that it propagates and the strength of the clear wood.
Softwood lumber producers have been using conventional drying systems (batch drying) for many years. The original premise of those systems was to design kilns that could dry large quantities of lumber at relatively low costs. Based on the evidence throughout the industry across Canada, those
requirements have been historically met and the industry has greatly benefitted from the existing system for decades. Currently, however, due to environmental pressures, increased processing costs, more stringent quality and moisture content requirements and the need to improve productivity, softwood lumber producers must consider alternative ways to dry lumber to ensure their competiveness in traditional markets and to explore opportunities for entering new markets. Drying faster without compromising the quality of the final product will position Canadian lumber producers to achieve the
aforementioned goals.
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The main objective of this study is to evaluate the potential of a short horizontal joint profile for glulam and CLT producers through an industrial assessment.
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The objective of the study is to identify current and available solutions for improving the fire resistance of wood I-joists. After an analysis and comparison of these technologies, the most promising solutions will be presented which will be suggested to wood I-joist manufacturers for potential further investigation.
Wood I-joists
Fire Resistant - Joints
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Several RF pressing trials were successfully conducted in the pilot plant at the Vancouver lab of FPInnovations, which aimed at thick LVL manufacturing, use of lignin-based PF resin as a binder and new plywood pressing method. A number of 3.5-in thick LVL billets were first RF-pressed for heavy-duty packaging applications with a pressing time of being shortened to about 25 min but with satisfactory bending MOE and MOR properties. Lignin PF resin (with 20wt% phenol replacement ratio) was prepared and used to make 13-ply spruce LVL. Compared to the control, there was no significant difference in both panel flatwise and edgewise bending MOE and MOR, as well as panel delamination resistance, when the lignin-based PF resin was applied. Further plywood RF heating trials with aluminum plate separation of panels demonstrated that the inclusion of the plates can help increase the thickness uniformity of plywood panels pressed with RF heating.
Economic analyses were conducted to determine the benefits of RF pressing for manufacturing LVL and plywood, and RF preheating of plywood. For RF pressing of LVL preliminary calculations demonstrated that RF pressing would generate aoubt $3.0 million CAD operating profit per year. It would also have 3.3% higher internal rate of return (IRR) and 1.25 years shorter payback period. For RF pressing of plywood, preliminary calculations indicated about $1.0 million CAD increase in operating profit annually for the RF pressing option, yielding a payback period of 3.95 years for purchasing and installing the new RF equipment. For RF pre-heating of plywood, the analysis showed that an increase of $4.7 million CAD in operating profit can be achieved annually and payback period is only 0.4 year. However, some further pilot plant work is required to establish the maximum closed assembly time of pre-heated plywood panels for industrial applications. PF adhesive formulations may also need to be changed in order to prevent glue dry-out after preheating.
In the Canadian OSB industry raw log moistures are generally thought to be a significant factor effecting mill operation. In 2012/13 an FPInnovations study was carried out to better understand the effects of log moisture content on the manufacturing operations at a western Canadian OSB mill. The information collected was intended to assist the mill to make informed decisions on log yard management and harvesting and also to understand the best possible scenarios for producing a quality product as cost effectively as possible. Of particular interest was whether benefits could be made by processing dryer wood as a means of increasing dryer capacity but without incurring significant costs resulting from lower strand quality, especially fines and the associated costs of increased resin usage and panel density.
The objective of this study was to examine new attributes and conduct economic analyses for composite CLT (CCLT) and value-added appearance-based CLT products manufactured with varying substitution of softwood lumber with structural composite lumber (SCL) and hardwood lumber. Incentives for including such materials could be aesthetic, structural and economic.
Structural and aesthetic property assessments were carried out on prototype CLT panels. Multiple CLT panel configurations (17) were evaluated to assess the effects of including hardwood and SCL materials in the layups. Presence of hardwood in the panels’ configuration generally led to higher checking and density. Because of the higher shrinkage of hardwood, the bondline suffered from more delamination. A lower density hardwood (aspen) was included in some configurations and exhibited a greater direct compatibility with current Canadian manufacturing process. Changes to this process, such as selecting a hardwood specific adhesive may lead to improvements.
SCL’s inclusion in the panels’ layup revealed to be fairly compatible with the current CLT manufacturing process. Both LVL and LSL products performed equally well or better than the reference lumber-made CLT panel for the bondline quality, dimensional stability and visual defects development. The efficiency of the manufacturing process of the prototype CLT panels was improved when EWP was included in the layup. The lesser amount of components and the readily flat surface of SCL may have a positive impact on the economics of CLT manufacturing due to an improved efficiency.
Substitution products evaluated are characterized by a higher market price than lumber. CLT made from a combination of LSL or LVL and softwood lumber would cost about $100/m3 more to get the same return if there were no changes in the manufacturing. The burden of this cost increase would have to be offset by unique series of attributes that would add value for the customer and/or by a greater manufacturing efficiency.
Glulam and CLT innovative manufacturing process and products development : effects of manufacturing parameters on the fire-resistance of CLT assemblies
This study was part of a broader project entitled Glulam and CLT Innovative Manufacturing Process and Product Development. The main objective of the current study is to evaluate the effect of CLT panels manufacturing parameters on its fire resistance. More specifically:
§ To evaluate the effect of CLT manufacturing (gluing) parameters on the heat delamination resistance under standard fire conditions;
§ To improve the fire-resistance of the CLT panels.
Ce projet consiste à faire la démonstration à l’échelle semi-industrielle d’un procédé de séchage de précision par haute fréquence en continu développé pour améliorer la qualité des produits séchés à la fin de la première ou au début de la deuxième transformation du bois. Plus spécifiquement, les objectifs du projet sont de :
Ø Concevoir, fabriquer et démontrer le fonctionnement d’un séchoir par haute fréquence en continu à l’échelle préindustrielle qui peut être intégré dans les usines de rabotage ou à l’entrée des usines de deuxième transformation;
Ø Transférer la technologie à un intégrateur devenant le fournisseur de l’équipement pour l’industrie canadienne de la transformation du bois.
Les objectifs de ce projet consistent à :
Ø Intégrer un module énergétique pouvant servir à démontrer la consommation énergétique thermique et ses coûts et également démontrer les gains énergétiques reliés à différentes stratégies de triage;
Ø Intégrer une base de données générique pour les essences de l’Ouest canadien.
Tel que présenté dans l’introduction, les objectifs initiaux relativement à l’intégration d’un module de reséchage et à la revue des pratiques de triage à travers le Canada ont été remplacées par la mise à jour du logiciel nécessaire et passant par une recodification du logiciel d’un langage Visual Basic à C#.
Log yard management has a significant effect on plywood/LVL manufacturing, particularly in the aspects of log conditioning, veneer processing and product quality. At present, log conditioning is seldom optimized due mainly to the variation of species and log diameter, log storage time and seasonal climate changes. The key objectives of this work were to: 1) develop a new computer program to simulate how log temperature and conditioning time change with regard to log diameter sorting and conditioning parameters; and 2) determine the optimal log diameter sorting points in order to achieve the best log conditioning for peeling.
A new computer simulation program FPLogcon™ was successfully developed to simulate how log temperature and conditioning time change with regard to log diameter sorting and conditioning parameters in the plywood and LVL mills. Through computer simulation and two case studies, the benefits of log diameter sorting were successfully demonstrated and the log diameter sorting breakpoint was further optimized.
For spruce in mill A, compared to no diameter sorting (control), the optimum diameter sorting could result in about 28.8% reduction in heating time, and about 17.5% increase in equivalent log volume within the target temperature range.
For lodgepole pine in mill B, in the summer, compared to no diameter sorting (control), the optimum log diameter sorting breakpoint was 9-in, resulting in about 15% reduction in equivalent heating time (no change in equivalent log volume). In the winter, the optimum log diameter sorting point was 8-in, leading to about 4.5% increase in equivalent heating time along with an 11.6% increase in equivalent log volume within the target temperature range.
For plywood/LVL mills, specific benefits of log diameter sorting will include increasing the uniformity of log temperature distribution and thus veneer quality, and reducing heating time and thus energy consumption, increasing lathe efficiency, and reducing downtime and spin-out rate during peeling. Mill results will be collected to validate the benefits of optimum log diameter sorting in the new fiscal year.
A round robin study using the CSA O112.9-10 standard was conducted with three (3) participating test laboratories in Canada as recommended by the Standards Council of Canada (SCC). The study included only the block shear test under three test conditions (dry, vacuum-pressure, and 9-cycle boil-dry-freeze). Test specimens were prepared using black spruce as substrate and phenol-resorcinol formaldehyde adhesive as the bonding agent.
All participating test laboratories passed the shear test of the CSA O112.9-10 standard in which the requirements are based on quantile parameters (median shear strength, median and lower quartile wood failure). This finding showed that the block shear test method of this adhesive standard was reproducible among three well-known test laboratories in Canada, all of which have been qualified by the SCC for the ISO 17025 accreditation program.
The test laboratories, however, exhibited some differences in terms of average shear strength and wood failure in the three test conditions. Some possible reasons were suggested for these differences.
Élément 4 : Initiative de recherche sur les bois feuillus - Développement de nouveaux procédés et de nouvelles technologies pour le secteur des bois feuillus ; Meilleures pratiques pour éviter la formation de gerces et de fentes sur les produits de bois feuillus. Première partie - Gerces et fentes : causes et prévention
La formation de gerces et de fentes sur les produits du bois est un problème majeur pour les fabricants de produits de bois feuillus et les consommateurs. En effet, des gerces et des fentes peuvent se former sur les billes, les sciages verts et séchés et sur les produits finaux et ce, en cours de fabrication, de séchage, de transformation, d’entreposage et d’utilisation finale des produits du bois. De nombreux facteurs internes et externes influent sur la formation de gerces et de fentes. Signalons notamment l’essence, la teneur en humidité du bois, la méthode d’entreposage, les procédés de séchage, la température, l’humidité relative, la vitesse de l’écoulement de l’air et les rayons solaires. Bien qu’il soit impossible d’empêcher complètement la formation de gerces et de fentes, il est toutefois possible d’en limiter le nombre à un niveau acceptable par l’application de mesures appropriées. Parmi ces mesures, on compte non seulement les meilleures pratiques relatives à la récolte, à l’entreposage, au débitage et au séchage du bois, mais aussi l’utilisation de dispositifs mécaniques et le contrôle des conditions ambiantes de l’utilisation des produits finaux. Le présent rapport fait état de connaissances scientifiques sur la nature de différents types de gerces susceptibles de se manifester sur divers produits du bois, les conditions qui en favorisent la formation et les mesures de contrôle connexes.
The present work aims at evaluating the combustibility characteristics (i.e. reaction to fire) of structural composite lumber (SCL) when tested in compliance with the cone calorimeter standard ISO 5660 [7, 8, 9]. More precisely, this study evaluates the heat release rate, total heat release, mass loss, effective heat of combustion, smoke obscuration as well as the presence of toxic gases when SCL products are tested in conformance with ISO 5660.
Moreover, this study is solely focused on SCL elements that are thick enough to act as semi-infinite solids (thermally thick solids), as opposed to typical thin combustible finish products. Tests data are also compared to those obtained for visually-graded solid wood specimens of the SPF species group.
Combustibility
Composite Lumber
Laminated products - Fire resistance
Structural Composites - Properties
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The key objective of this study is to analyze full-scale fire-resistance tests conducted on structural composite lumber (SCL), namely laminated veneer lumber (LVL), parallel strand lumber (PSL) and laminated strand lumber (LSL). A sub-objective is to evaluate the encapsulation performance of Type X gypsum board directly applied to SCL beams and its contribution to fire-resistance of wood elements.
The test data is being used to further support the applicability of the newly developed Canadian calculation method for mass timber elements, recently implemented as Annex B of CSA O86-14.
The objective of this project was to update the JAFA, an innovative tool developed by FPInnovations aimed at providing valuable information for manufacturing finger jointed lumber in a continuous process.
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